Array Methods
Array methods are built-in functions that allow you to perform operations on arrays in a concise and efficient way. They provide a powerful set of tools for manipulating and working with arrays without the need for manual loops.
Here are some of the most commonly used array methods in JavaScript:
1. map():
Use: Creates a new array by applying a given function to each element of the original array.
Example:
const numbers = [1, 2, 3, 4, 5];
const doubled = numbers.map(number => number * 2);
console.log(doubled); // Output: [2, 4, 6, 8, 10]
2. filter():
Use: Creates a new array containing only the elements that satisfy a given condition.
Example:
const ages = [18, 25, 16, 30, 20];
const adults = ages.filter(age => age >= 18);
console.log(adults); // Output: [18, 25, 30, 20]
3. forEach():
Use: Executes a provided function once for each element in the array.
Example:
const names = ["Alice", "Bob", "Charlie"];
names.forEach(name => console.log(name));
4. sort():
Use: Sorts the elements of an array in place and returns the sorted array.
Example:
const fruits = ["banana", "apple", "orange"];
fruits.sort();
console.log(fruits); // Output: ["apple", "banana", "orange"]
5. join():
Use: Creates and returns a new string by concatenating all of the elements in an array, separated by a specified separator.
Example:
const fruits = ["Apple", "Banana", "Cherry"];
const result = fruits.join(" - ");
console.log(result); // Output: "Apple - Banana - Cherry"
6. slice():
Use: Returns a shallow copy of a portion of an array into a new array selected from start to end (end not included).
Example:
const numbers = [1, 2, 3, 4, 5];
const sliced = numbers.slice(1, 3);
console.log(sliced); // Output: [2, 3]
7. concat():
Use: Creates a new array by concatenating the specified arrays or values to the end of the current array.
Example:
const array1 = [1, 2, 3];
const array2 = [4, 5, 6];
const combined = array1.concat(array2);
console.log(combined); // Output: [1, 2, 3, 4, 5, 6]
8. includes():
Use: Determines whether an array includes a certain value among its entries, returning true or false as appropriate.
Example:
const numbers = [1, 2, 3, 4, 5];
const includesThree = numbers.includes(3);
console.log(includesThree); // Output: true
9. push():
Use: Adds one or more elements to the end of an array and returns the new length of the array.
Example:
const numbers = [1, 2, 3];
numbers.push(4, 5);
console.log(numbers); // Output: [1, 2, 3, 4, 5]
10. pop():
Use: Removes the last element from an array and returns that element.
Example:
const numbers = [1, 2, 3];
const last = numbers.pop();
console.log(numbers); // Output: [1, 2]
console.log(last); // Output: 3